Nanostructured Indium Oxide Thin Films as a Room Temperature Toluene Sensor

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Toluene gas poses significant respiratory health risks, necessitating sensitive detection methods.
• Developing effective and affordable gas sensors for environmental monitoring is crucial.

Purpose of the Study:

• To fabricate and characterize indium oxide (In2O3) thin films for room temperature toluene gas sensing.
• To investigate the effect of substrate temperature on the structural, morphological, and gas-sensing properties of In2O3 films.

Main Methods:

• Spray pyrolysis deposition of In2O3 films on glass substrates at varying temperatures (350-500 °C).
• Characterization using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), and Raman spectroscopy.
• Gas sensing performance evaluation towards 50 ppm toluene at room temperature.

Main Results:

• In2O3 films exhibited a cubic structure with preferred (222) orientation, increasing crystallite size with substrate temperature.
• FESEM and TEM confirmed nanostructured films with uniform grain distribution and partial agglomeration at higher temperatures.
• Optimal gas-sensing performance for 50 ppm toluene at room temperature was achieved with good stability, response, and recovery times.

Conclusions:

• Spray pyrolysis is a viable method for producing In2O3 films for gas sensing applications.
• Substrate temperature significantly influences the structural and morphological properties, impacting gas-sensing performance.
• The developed In2O3 sensor shows promise for effective and stable toluene detection at room temperature.